44 male postinfarction volunteers were divided into 4 groups and submitted to performance tests. Groups I and II consisted of 24 patients, 12 of whom followed a 2-month physical training program, while the other 12 served as controls. Groups III and IV (10 patients each) were included in a 10-month double-blind crossover study with lidoflazine 240 mg/day vs. placebo. The cardiovascular adaptation of the patients treated for 5 months with lidoflazine had two features in common with that observed after 2 months of physical training, namely an increase in maximal exercise capacity and, during submaximal exercise tests, a decrease in heart rate compensated for by an increase in stroke volume. In contrast to physical training, treatment with lidoflazine did not improve the peripheral oxygen consumption by the muscles.